Drive device

ABSTRACT

A drive device includes a fluid coupling, a rotary electrical machine, and a damper device. The fluid coupling includes an input unit and an output unit. The input unit includes an impeller. The output unit includes a turbine. The rotary electrical machine includes a first stator and a rotor. The first stator is disposed in a non-rotatable manner. The rotor is attached to the output unit. The damper device is disposed axially adjacent to the fluid coupling. The damper device is connected to the input unit.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Japanese Patent Application No.2020-150313 filed Sep. 8, 2020. The entire contents of that applicationare incorporated by reference herein in their entirety.

TECHNICAL FIELD

The present invention relates to a drive device.

BACKGROUND ART

Japan Laid-open Patent Application Publication No. 2005-201402 disclosesa drive device disposed between an engine and a transmission. The drivedevice includes a rotary electrical machine and a torque converter.

In the drive device described above, the engine and the rotaryelectrical machine are directly connected to each other. Hence, theengine cannot be disconnected from the rotary electrical machine inregenerative operation of the rotary electrical machine. Because ofthis, regenerative efficiency degrades in the rotary electrical machinedue to friction loss of the engine and/or so forth.

It is an object of the present invention to enhance regenerativeefficiency in a rotary electrical machine.

BRIEF SUMMARY

A drive device according to an aspect of the present invention includesa fluid coupling, a rotary electrical machine, and a damper device. Thefluid coupling includes an input unit and an output unit. The input unitincludes an impeller. The output unit includes a turbine. The rotaryelectrical machine includes a first stator and a rotor. The first statoris disposed in a non-rotatable manner. The rotor is attached to theoutput unit. The damper device is disposed axially adjacent to the fluidcoupling. The damper device is connected to the input unit.

According to the configuration, the rotor of the rotary electricalmachine is attached to the output unit of the fluid coupling. Besides, atorque outputted from an engine is transmitted to the input unit of thefluid coupling through the damper device. In other words, the fluidcoupling intervenes between the engine and the rotor of the rotaryelectrical machine, whereby the engine and the rotor are made rotatablerelative to each other. Because of this, friction loss of the engineand/or so forth can be reduced in regenerative operation of the rotaryelectrical machine, whereby regenerative efficiency can be enhanced.Furthermore, a clutch is not required to be provided between the damperdevice and the fluid coupling in order to disconnect the engine and therotary electrical machine from each other.

Preferably, the output unit includes a cover coupled to the turbine. Thecover and the turbine form at least part of an outer shell of the fluidcoupling. The impeller is opposed to the turbine inside the outer shell.

Preferably, the rotor is attached to the outer shell.

Preferably, the drive device further includes a transmission shaft. Thetransmission shaft extends to penetrate the outer shell. Thetransmission shaft connects the damper device and the impeller to eachother.

Preferably, the drive device further includes a first bearing member.The first bearing member is fixed to a crankshaft of an engine andsupports the transmission shaft such that the transmission shaft is maderotatable.

Preferably, the outer shell of the fluid coupling includes an innertubular portion axially extending from an inner peripheral end thereof.The transmission shaft axially extends inside the inner tubular portion.The drive device further includes a seal member and a second bearingmember. The seal member is disposed between the inner tubular portionand the transmission shaft. The second bearing member is fixed to eitherthe crankshaft of the engine or a member attached to the crankshaft. Thesecond bearing member supports the outer shell of the fluid couplingfrom radially outside such that the outer shell is made rotatable.

Preferably, the second bearing member supports the inner tubular portionsuch that the inner tubular portion is made rotatable.

Preferably, the fluid coupling further includes a lock-up clutch deviceconfigured to allow and block transmission of a torque between the inputunit and the output unit.

Preferably, the impeller includes an impeller shell, an impeller blade,an impeller hub, and a first one-way clutch. The impeller blade isattached to the impeller shell. The impeller hub is a member, to whichthe torque is inputted. The first one-way clutch is disposed between theimpeller shell and the impeller hub. The lock-up clutch device isconfigured to be unitarily rotated with the impeller hub.

Preferably, the impeller includes an impeller shell, an impeller blade,an impeller hub, and a first one-way clutch. The impeller blade isattached to the impeller shell. The impeller hub is a member, to whichthe torque is inputted. The first one-way clutch is disposed between theimpeller shell and the impeller hub.

Preferably, the damper device includes an input plate, an output member,and an elastic member. The input plate is attached to the crankshaft ofthe engine. The output member outputs the torque to the transmissionshaft. The elastic member elastically couples the input plate and theoutput member.

Preferably, the elastic member is a coil spring. A center of the elasticmember does not overlap the rotor of the rotary electrical machine in anaxial view.

Preferably, the drive device further includes a starter ring gear. Thestarter ring gear is configured to transmit a power to the crankshaft ofthe engine. The starter ring gear is disposed radially outside a coilend of the rotary electrical machine. The starter ring gear overlaps thecoil end in a radial view.

Preferably, the drive device further includes an angle sensor. The anglesensor is disposed radially inside a center of a torus of the fluidcoupling. The angle sensor is disposed to overlap the torus in theradial view.

Overall, according to the present invention, regenerative efficiency canbe enhanced in a rotary electrical machine.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a drive device.

FIG. 2 is a cross-sectional view of a drive device according to amodification.

DETAILED DESCRIPTION

A drive device according to the present preferred embodiment will behereinafter explained with reference to drawings. It should be notedthat in the following explanation, the term “axial direction” refers toan extending direction of a rotational axis of the drive device. Theterm “first side in the axial direction” corresponds to the left side inFIG. 1, whereas the term “second side in the axial direction”corresponds to the right side in FIG. 1. An engine is disposed on thefirst side of the drive device in the axial direction, whereas atransmission is disposed on the second side of the drive device in theaxial direction. On the other hand, the term “circumferential direction”refers to a circumferential direction of an imaginary circle about therotational axis, whereas the term “radial direction” refers to a radialdirection of the imaginary circle about the rotational axis.

[Drive Device]

As shown in FIG. 1, a drive device 100 includes a torque converter 2(exemplary fluid coupling), a rotary electrical machine 3, and atransmission shaft 4. Besides, the drive device 100 includes a damperdevice 5, a first bearing member 6 a, a second bearing member 6 b, aseal member 7, and an angle sensor 8. The drive device 100 is disposedin a torque transmission path extending from the engine (not shown inthe drawings) to the transmission.

[Torque Converter]

The torque converter 2 is configured such that a torque is inputtedthereto from the first side in the axial direction and is outputtedtherefrom to the second side in the axial direction. It should be notedthat, in the present preferred embodiment, the torque converter 2 isconfigured such that a torque is inputted thereto from the engine and isoutputted therefrom to the transmission.

The torque converter 2 includes an input unit 2 a and an output unit 2b. Torque transmission is enabled from the input unit 2 a to the outputunit 2 b through hydraulic oil contained in the torque converter 2. Theinput unit 2 a and the output unit 2 b are rotatable relative to eachother. The input unit 2 a of the torque converter 2 includes an impeller23. The output unit 2 b of the torque converter 2 includes a cover 21and a turbine 22.

The torque converter 2 includes a second stator 24 and a lock-up clutchdevice 25. The torque converter 2 is rotated about a rotational axis O.The torque converter 2 is configured to transmit the torque from theengine to the transmission through a fluid.

[Cover]

The cover 21 composes part of an outer shell of the torque converter 2.The cover 21 is coupled to the turbine 22. The cover 21 includes a coverbody 21 a, an outer tubular portion 21 b, and a boss portion 21 c(exemplary inner tubular portion). The cover body 21 a is a disc-shapedmember including an opening in the middle thereof. The outer tubularportion 21 b extends from the outer peripheral end of the cover body 21a to the second side in the axial direction.

The boss portion 21 c extends from the inner peripheral end of the coverbody 21 a in the axial direction. When described in detail, the bossportion 21 c extends from the inner peripheral end of the cover body 21a to the first side in the axial direction. It should be noted that theboss portion 21 c can extend from the inner peripheral end of the coverbody 21 a to the second side in the axial direction. The boss portion 21c has a cylindrical shape. The boss portion 21 c is bent radially inwardat the distal end thereof

[Turbine]

The turbine 22 is fixed to the cover 21. The turbine 22 is unitarilyrotated with the cover 21. The turbine 22 composes the outer shell ofthe torque converter 2 together with the cover 21. The turbine 22includes a turbine shell 22 a, a plurality of turbine blades 22 b, aturbine hub 22 c, and a turbine core 22 d.

The turbine shell 22 a composes part of the outer shell of the torqueconverter 2. It should be noted that the turbine shell 22 a composes theouter shell of the torque converter 2 together with the turbine hub 22 cand the cover 21. The turbine blades 22 b are fixed to the inner side ofthe turbine shell 22 a.

The turbine hub 22 c is fixed to the inner peripheral end of the turbineshell 22 a. The turbine hub 22 c extends from the inner peripheral endof the turbine shell 22 a to the second side in the axial direction. Theturbine hub 22 c has a cylindrical shape. The turbine hub 22 c isprovided with splines on the inner peripheral surface thereof. An inputshaft 101 of the transmission is attached to the turbine hub 22 c. Whendescribed in detail, the input shaft 101 of the transmission isspline-coupled to the turbine hub 22 c. The turbine hub 22 c outputs thetorque to the input shaft 101. It should be noted that in the presentpreferred embodiment, the turbine hub 22 c is provided as a memberseparated from the turbine shell 22 a. However, the turbine hub 22 c canbe provided together with the turbine shell 22 a as a single member.

[Impeller]

The impeller 23 is disposed inside the outer shell composed of the cover21 and the turbine 22. The impeller 23 is axially opposed to the turbine22. The impeller 23 includes an impeller shell 23 a, a plurality ofimpeller blades 23 b, an impeller hub 23 c, an impeller core 23 d, and afirst one-way clutch 23 e.

The impeller shell 23 a is attached to the impeller hub 23 c through thefirst one-way clutch 23 e. The impeller blades 23 b are fixed to theinner surface of the impeller shell 23 a.

The impeller hub 23 c is a member to which the torque outputted from theengine is inputted through the transmission shaft 4. The impeller hub 23c is attached to the inner peripheral end of the impeller shell 23 athrough the first one-way clutch 23 e. The impeller hub 23 c is providedwith splines on the inner peripheral surface thereof.

The first one-way clutch 23 e is disposed between the impeller shell 23a and the impeller hub 23 c. The first one-way clutch 23 e is configuredto transmit a torque, inputted thereto from the transmission shaft 4, tothe impeller shell 23 a but is configured not to transmit a torque,inputted thereto from the impeller shell 23 a, to the transmission shaft4. When described in detail, the first one-way clutch 23 e is configuredto transmit a torque, inputted thereto from the impeller hub 23 c, tothe impeller shell 23 a but is configured not to transmit a torque,inputted thereto from the impeller shell 23 a, to the impeller hub 23 c.

[Second Stator]

The second stator 24 is a mechanism for regulating the flow of hydraulicoil returning from the turbine 22 to the impeller 23. The second stator24 is disposed between the turbine 22 and the impeller 23. The secondstator 24 includes a stator shell 24 a, a plurality of stator blades 24b provided on the outer peripheral surface of the stator shell 24 a, asecond stator core 24 c, and a second one-way clutch 24 d.

A first thrust bearing 27 a is disposed between the second stator 24 andthe turbine 22, whereas a second thrust bearing 27 b is disposed betweenthe second stator 24 and the impeller 23.

The second one-way clutch 24 d is attached to the inner peripheral endof the stator shell 24 a. Besides, the second one-way clutch 24 d issupported by a stationary shaft 102 having a tubular shape. Thestationary shaft 102 extends between the outer peripheral surface of thetransmission shaft 4 and the inner peripheral surface of the turbine hub22 c. The stationary shaft 102 is disposed in a non-rotatable manner.

[Lock-Up Clutch Device]

The lock-up clutch device 25 is configured to allow and blocktransmission of a torque between the input unit 2 a and the output unit2 b. In other words, the lock-up clutch device 25 is configured to allowand block transmission of the torque between the turbine 22 and theimpeller 23. In the present preferred embodiment, the lock-up clutchdevice 25 allows and blocks transmission of the torque between theturbine 22 and the impeller 23 through the cover 21.

The lock-up clutch device 25 is disposed between the cover 21 and theimpeller 23 and is configured to mechanically couple and decouple theboth. The lock-up clutch device 25 includes a piston plate 25 a and afriction material 25 b.

The piston plate 25 a is supported by the impeller hub 23 c so as to bemovable in the axial direction. Besides, the piston plate 25 a isconfigured to be unitarily rotated with the impeller hub 23 c. Whenmoved toward the cover 21, the piston plate 25 a is engaged by frictionwith the cover 21 and is unitarily rotated therewith.

The piston plate 25 a has a disc shape and includes an opening in themiddle thereof. The piston plate 25 a is provided with the frictionmaterial 25 b fixed to the cover 21-side surface of the outer peripheralend thereof. The friction material 25 b has an annular shape. When thefriction material 25 b is pressed against the cover 21, the torque istransmitted from the piston plate 25 a to the cover 21. In other words,the friction material 25 b attached to the piston plate 25 a is providedas a clutch part.

[Rotary Electrical Machine]

The rotary electrical machine 3 functions as an electric motor forrotating and driving a drive wheel. Besides, the rotary electricalmachine 3 also functions as a power generator. For example, the rotaryelectrical machine 3 functions as the power generator in deceleration.

The rotary electrical machine 3 is disposed radially outside the torqueconverter 2. The rotary electrical machine 3 overlaps the torqueconverter 2 in a radial view. The rotary electrical machine 3 includes afirst stator 31 and a rotor 32. The rotary electrical machine 3 is madein shape of an annulus about the rotational axis O.

[First Stator]

The first stator 31 is disposed in a non-rotatable manner. Specifically,the first stator 31 is attached to a housing 103. The first stator 31can be directly attached to the housing 103, or alternatively, can beindirectly attached thereto.

The first stator 31 has an annular shape. The first stator 31 includes afirst stator core 31 a, a first coil end 31 b, and a second coil end 31c.

The first stator core 31 a has a cylindrical shape. The first statorcore 31 a is fixed to the housing 103 through an attachment member 31 d.The first stator core 31 a overlaps the torque converter 2 in the radialview.

The first stator core 31 a is formed by laminating a plurality ofmagnetic steel plates. A stator coil is wound about the first statorcore 31 a. When described in detail, the stator coil is inserted into aplurality of slots produced between a plurality of teeth of the firststator core 31 a.

The first and second coil ends 31 b and 31 c compose part of the statorcoil. Specifically, the stator coil axially extends in part from thefirst stator core 31 a as the first and second coil ends 31 b and 31 c.

The first and second coil ends 31 b and 31 c protrude from the firststator core 31 a in opposite directions to each other. In the presentpreferred embodiment, the first coil end 31 b protrudes from the firststator core 31 a to the first side in the axial direction, whereas thesecond coil end 31 c protrudes from the first stator core 31 a to thesecond side in the axial direction. Each of the first and second coilends 31 b and 31 c is entirely made in shape of an annulus about therotational axis O.

The first coil end 31 b does not overlap the torque converter 2 in theradial view. The first coil end 31 b overlaps the damper device 5 in theradial view. On the other hand, the first stator core 31 a overlaps thetorque converter 2 in the radial view.

The second coil end 31 c overlaps the torque converter 2 in the radialview. When described in detail, the second coil end 31 c overlaps atorus of the torque converter 2. It should be noted that the torus ofthe torque converter 2 means a space enclosed by the turbine shell 22 aand the impeller shell 23 a.

[Rotor]

The rotor 32 is configured to be rotated about the rotational axis O.The rotor 32 is attached to the output unit 2 b of the torque converter2. When described in detail, the rotor 32 is attached to the outer shellof the torque converter 2. It should be noted that in the presentpreferred embodiment, the rotor 32 is attached to the outer tubularportion 21 b of the cover 21. In other words, the rotor 32 is attachedto the outer peripheral surface of the cover 21.

The rotor 32 has a cylindrical shape and is disposed radially inside thefirst stator 31. In other words, the rotary electrical machine 3according to the present preferred embodiment is of an inner rotor type.The rotor 32 is opposed at the outer peripheral surface thereof to theinner peripheral surface of the first stator 31 at an interval.

[Damper Device]

The damper device 5 is disposed adjacent to the torque converter 2 inthe axial direction. When described in detail, the damper device 5 isdisposed between the engine and the torque converter 2. The damperdevice 5 is a device that a torque is inputted thereto from the engineand is outputted therefrom to the torque converter 2.

The damper device 5 is attached to a crankshaft 104 of the engine. Thedamper device 5 is disposed to be rotatable about the rotational axis O.The damper device 5 is connected to the input unit 2 a of the torqueconverter 2. When described in detail, the damper device 5 is connectedto the impeller 23 of the input unit 2 a through the transmission shaft4. Besides, a clutch, by which the engine and the rotary electricalmachine 3 are disconnected from each other, does not intervene betweenthe damper device 5 and the torque converter 2.

The damper device 5 includes an input plate 51, an output member 52, aretaining plate 53, and a plurality of elastic members 54.

The input plate 51 is made in shape of a disc including an opening inthe middle thereof. The input plate 51 includes a plurality ofaccommodation portions 511. Each accommodation portion 511 extends inthe circumferential direction. The accommodation portions 511 arealigned in the circumferential direction.

The input plate 51 is attached to the crankshaft 104. When described indetail, the input plate 51 is attached at the inner peripheral endthereof to the crankshaft 104. The input plate 51 is bent at the outerperipheral end thereof in the axial direction. In the present preferredembodiment, the input plate 51 is bent at the outer peripheral endthereof to the second side in the axial direction.

The input plate 51 is provided with a starter ring gear 9 attached tothe outer peripheral surface thereof. The ring gear 9 is configured totransmit a torque to the crankshaft 104 through the input plate 51. Thering gear 9 is disposed radially outside the first coil end 31 b. Thering gear 9 overlaps the first coil end 31 b in the radial view.

The output member 52 outputs the torque to the transmission shaft 4. Theoutput member 52 includes an output plate 521 and an output hub 522. Theoutput plate 521 is fixed to the output hub 522 by rivets (not shown inthe drawings) and/or so forth. It should be noted that the output plate521 can be integrated with the output hub 522 as a single member.

The output plate 521 is disposed adjacent to the input plate 51. Whendescribed in detail, the output plate 521 is disposed on the second sideof the input plate 51 in the axial direction.

The output plate 521 includes a plurality of window portions 521 a. Eachwindow portion 521 a extends in the circumferential direction. Thewindow portions 521 a are disposed away from each other at intervals inthe circumferential direction. The window portions 521 a are provided incorresponding positions to the accommodation portions 511 of the inputplate 51.

The output hub 522 is configured to be unitarily rotated with thetransmission shaft 4. When described in detail, the output hub 522 isprovided with splines on the inner peripheral surface thereof. Besides,the transmission shaft 4 is spline-coupled to the output hub 522.

The output hub 522 includes a protruding portion 522 a protruding to thesecond side in the axial direction. The protruding portion 522 a has atubular shape. The protruding portion 522 a is disposed radially outsidethe boss portion 21 c of the cover 21. The protruding portion 522 a andthe boss portion 21 c overlap each other in the radial view.

The retaining plate 53 is configured to be unitarily rotated with theoutput member 52. For example, the retaining plate 53 is attached to theoutput plate 521 by rivets (not shown in the drawings) and/or so forth.The input plate 51 is disposed between the retaining plate 53 and theoutput plate 521.

The retaining plate 53 includes a plurality of window portions 531. Eachwindow portion 531 extends in the circumferential direction. The windowportions 531 are disposed away from each other at intervals in thecircumferential direction. The window portions 531 are provided incorresponding positions to the window portions 521 a of the output plate521.

The elastic members 54 are configured to elastically couple the inputplate 51 and the output member 52 therethrough. The elastic members 54are, for instance, coil springs. Each elastic member 54 is disposedinside a space defined by each accommodation portion 511 of the inputplate 51, each window portion 521 a of the output plate 521, and eachwindow portion 531 of the retaining plate 53. Each elastic member 54 isdisposed such that the center (C1) thereof does not overlap the rotor 32in an axial view.

[Transmission Shaft]

The transmission shaft 4 extends along the rotational axis O. Thetransmission shaft 4 is rotatable about the rotational axis O. Thetransmission shaft 4 extends while penetrating the outer shell of thetorque converter 2. When described in detail, the transmission shaft 4axially extends through the interior of the boss portion 21 c of thecover 21. The transmission shaft 4 extends from outside to inside of thetorque converter 2 through the interior of the boss portion 21 c.

The transmission shaft 4 is configured to transmit the torque, inputtedthereto from the engine, to the impeller 23. The transmission shaft 4 isconnected to the damper device 5 on the outside of the torque converter2. When described in detail, the transmission shaft 4 is spline-coupledto the output member 52 of the damper device 5.

The transmission shaft 4 is connected to the impeller 23 in the interiorof the torque converter 2. When described in detail, the transmissionshaft 4 is spline-coupled to the impeller hub 23 c. Because of this, thetorque, outputted from the damper device 5, is transmitted to theimpeller 23 through the transmission shaft 4. In other words, the damperdevice 5 is connected to the impeller 23 through the transmission shaft4.

[First Bearing Member]

The first bearing member 6 a is fixed to the crankshaft 104 of theengine. When described in detail, the first bearing member 6 a is fittedinto a recess of the crankshaft 104. The first bearing member 6 asupports the transmission shaft 4 such that the transmission shaft 4 ismade rotatable. When described in detail, the transmission shaft 4 isfitted at axially first side one of the ends thereof to the firstbearing member 6 a.

[Second Bearing Member]

The second bearing member 6 b is fixed to the damper device 5. Whendescribed in detail, the second bearing member 6 b is fitted into theprotruding portion 522 a of the output hub 522 of the damper device 5.The second bearing member 6 b supports the cover 21 from radiallyoutside. When described in detail, the boss portion 21 c of the cover 21is fitted into the second bearing member 6 b. In other words, the secondbearing member 6 b is disposed between the damper device 5 and the cover21. Because of this, the damper device 5 and the cover 21 are rotatedrelative to each other.

[Seal Member]

The seal member 7 is disposed between the boss portion 21 c and thetransmission shaft 4. The seal member 7 has an annular shape and sealsbetween the boss portion 21 c and the transmission shaft 4. The sealmember 7 is configured to prevent the hydraulic oil, circulating in theinterior of the torque converter 2, from leaking outside.

[Angle Sensor]

The angle sensor 8 is configured to detect the rotational speed of therotor 32 of the rotary electrical machine 3. When described in detail,the angle sensor 8 is configured to detect the rotational speed of theouter shell of the torque converter 2 unitarily rotated with the rotor32. It should be noted that in the present preferred embodiment, theangle sensor 8 is configured to detect the rotational speed of theturbine hub 22 c. The angle sensor 8 is, for instance, a resolver.

The angle sensor 8 is disposed to overlap the torus of the torqueconverter 2 in a radial view. When described in detail, the angle sensor8 overlaps the turbine 22 in the radial view.

The angle sensor 8 is disposed radially inside the center (C2) of thetorus of the torque converter 2. The angle sensor 8 is disposed radiallyinside the turbine blades 22 b. It should be noted that the center C2 ofthe torus is the center of a space enclosed by the turbine core 22 d andthe impeller core 23 d. It should be also noted that when the torqueconverter 2 is of a coreless type, the center C2 of the torus isdetermined under the assumption that the torque converter 2 includes animpeller core and a turbine core.

[Modifications]

One preferred embodiment of the present invention has been explainedabove. However, the present invention is not limited to the above, and avariety of changes can be made without departing from the gist of thepresent invention.

Modification 1

As shown in FIG. 2, the rotary electrical machine 3 can be disposed tooverlap the torque converter 2 in an axial view. Specifically, therotary electrical machine 3 can be disposed axially adjacent to thetorque converter 2. Preferably, the rotary electrical machine 3 isdisposed on the second side of the torque converter 2 in the axialdirection. In other words, the torque converter 2, the rotary electricalmachine 3, and the transmission (not shown in the drawings) are disposedin this order in the axial direction.

The rotor 32 of the rotary electrical machine 3 is attached to, forinstance, the turbine 22. For example, the rotor 32 is attached toeither the turbine shell 22 a or the turbine hub 22 c. The rotor 32 isattached to the torque converter 2 in a position located radiallyoutside or inside the center C2 of the torus of the torque converter 2.

Modification 2

As shown in FIG. 2, the first coil end 31 b can be bent radiallyoutward. When described in detail, the first coil end 31 b is bentradially outward from a base portion. It should be noted that the baseportion is one of end portions of the first coil end 31 b and is locatedclose to the first stator core 31 a in the axial direction. By contrast,a tip portion of the first coil end 31 b is the other of the endportions of the first coil end 31 b and is located away from the firststator core 31 a in the axial direction.

The first coil end 31 b overlaps the torus of the torque converter 2 inthe radial view. When described in detail, the first coil end 31 boverlaps the turbine 22 in the radial view.

The first coil end 31 b is configured to increase in outer radius andinner radius from the base portion to the tip portion. It should benoted that the radius of the first coil end 31 b refers to distance fromthe rotational axis O to a target position on the first coil end 31 b.Because of this, the base portion and the tip portion of the first coilend 31 b are substantially equal in radial dimension.

Modification 3

As shown in FIG. 2, the rotary electrical machine 3 can further includea field coil 33. In other words, the rotary electrical machine 3includes the first stator 31, the rotor 32, and the field coil 33.

In the modification 3, the rotor 32 is made in form of a so-called clawpole type. Specifically, the rotor 32 includes a plurality of first clawpoles 32 a and a plurality of second claw poles 32 b. The first clawpoles 32 a and the second claw poles 32 b are alternately disposed inthe circumferential direction. The first claw poles 32 a and the secondclaw poles 32 b are each made of a magnetic material such as iron. Thefirst claw poles 32 a and the second claw poles 32 b are insulated fromeach other. For example, a non-magnetic material such as aluminum isdisposed between adjacent first and second claw poles 32 a and 32 b.

The rotor 32 includes a support member 32 c. The support member 32 csupports the first claw poles 32 a and the second claw poles 32 b. Thesupport member 32 c is attached to the turbine 22. When described indetail, the support member 32 c is attached to the turbine hub 22 c.

The field coil 33 is disposed radially inside the rotor 32. The fieldcoil 33 has a cylindrical shape. The field coil 33 is opposed at theouter peripheral surface thereof to the inner peripheral surface of therotor 32 at an interval. The field coil 33 is disposed in anon-rotatable manner. For example, the field coil 33 is attached to ahousing or so forth.

The field coil 33 is configured to excite the rotor 32 by applying amagnetizing force to the rotor 32. Electric current to be supplied tothe field coil 33 is regulated by a current control unit (not shown inthe drawings), whereby the magnetizing force applied to the rotor 32 canbe regulated, and further, induced voltage to be generated in the firststator 31 can be regulated.

When electric current is supplied to the field coil 33, the first andsecond claw poles 32 a and 32 b are excited. For example, the first clawpoles 32 a are excited into N poles, whereas the second claw poles 32 bare excited into S poles. Thus, in the rotor 32, the N poles and the Spoles are alternately arranged in the circumferential direction. Whenthe rotor 32 is rotated, the induced voltage (induced electromotiveforce) is generated in the first stator 31.

Modification 4

In the preferred embodiment described above, the impeller 23 includesthe first one-way clutch 23 e. However, the composition of the impeller23 is not limited to this. In other words, the impeller 23 may notinclude the first one-way clutch 23 e. In this case, for instance, theimpeller shell 23 a is fixed to the impeller hub 23 c by rivets and/orso forth.

Modification 5

In the preferred embodiment described above, the rotary electricalmachine 3 is of an inner rotor type. Alternatively, the rotaryelectrical machine 3 can be of an outer rotor type.

Modification 6

The second one-way clutch 24 d can be disposed on the second side of thecenter C2 of the torus of the torque converter 2 in the axial direction.In other words, the second one-way clutch 24 d can be disposed on thesecond side of the stator blades 24 b in the axial direction. In thiscase, the second one-way clutch 24 d does not overlap the stator blades24 b in a radial view.

Modification 7

In the preferred embodiment described above, the piston plate 25 a isconfigured to be unitarily rotated with the impeller hub 23 c. However,the configuration of the piston plate 25 a is not limited to this. Forexample, the piston plate 25 a can be configured to be unitarily rotatedwith the impeller shell 23 a.

Modification 8

In the preferred embodiment described above, the cover 21 is disposed onthe first side of the turbine 22 in the axial direction. However, thestructure of the torque converter 2 is not limited to this. For example,the cover 21 can be disposed on the second side of the turbine 22 in theaxial direction. In other words, the turbine 22 and the cover 21 aredisposed in this order from the engine side. In this case, thetransmission shaft 4 penetrates the interior of the turbine hub 22 c ofthe turbine 22. The turbine hub 22 c herein corresponds to the innertubular portion of the present invention.

REFERENCE SIGNS LIST

-   2 Torque converter-   2 a Input unit-   2 b Output unit-   21 Cover-   22 Turbine-   23 Impeller-   23 a Impeller shell-   23 b Impeller blade-   23 c Impeller hub-   23 e First one-way clutch-   25 Lock-up clutch device-   3 Rotary electrical machine-   31 First stator-   32 Rotor-   4 Transmission shaft-   5 Damper device-   51 Input plate-   52 Output member-   54 Elastic member-   6 a First bearing member-   6 b Second bearing member-   7 Seal member-   8 Angle sensor-   9 Ring gear

What is claimed is:
 1. A drive device comprising: a fluid couplingincluding an input unit and an output unit, the input unit including animpeller, the output unit including a turbine; a rotary electricalmachine including a first stator and a rotor, the first stator disposedin a non-rotatable manner, the rotor attached to the output unit; and adamper device disposed axially adjacent to the fluid coupling, thedamper device connected to the input unit.
 2. The drive device accordingto claim 1, wherein the output unit includes a cover coupled to theturbine, the cover and the turbine form at least part of an outer shellof the fluid coupling, and the impeller is opposed to the turbine insidethe outer shell.
 3. The drive device according to claim 2, wherein therotor is attached to the outer shell.
 4. The drive device according toclaim 2, further comprising: a transmission shaft extending to penetratethe outer shell, the transmission shaft connecting the damper device andthe impeller to each other.
 5. The drive device according to claim 4,further comprising: a first bearing member fixed to a crankshaft of anengine, the first bearing member supporting the transmission shaft suchthat the transmission shaft is rotatable.
 6. The drive device accordingto claim 4, further comprising: a seal member; and a second bearingmember, wherein the outer shell of the fluid coupling includes an innertubular portion axially extending at an inner peripheral end thereof,the transmission shaft axially extends inside the inner tubular portion,the seal member is disposed between the inner tubular portion and thetransmission shaft, the second bearing member is fixed to either acrankshaft of an engine or a member attached to the crankshaft, and thesecond bearing member supports the outer shell of the fluid couplingfrom radially outside such that the outer shell is rotatable.
 7. Thedrive device according to claim 6, wherein the second bearing membersupports the inner tubular portion such that the inner tubular portionis rotatable.
 8. The drive device according to claim 1, wherein thefluid coupling further includes a lock-up clutch device configured toallow and block transmission of a torque between the input unit and theoutput unit.
 9. The drive device according to claim 8, wherein theimpeller includes an impeller shell, an impeller blade attached to theimpeller shell, an impeller hub to which the torque is inputted, and afirst one-way clutch disposed between the impeller shell and theimpeller hub, and the lock-up clutch device is configured to beunitarily rotated with the impeller hub.
 10. The drive device accordingto claim 1, wherein the impeller includes an impeller shell, an impellerblade attached to the impeller shell, an impeller hub to which a torqueis inputted, and a first one-way clutch disposed between the impellershell and the impeller hub.
 11. The drive device according to claim 1,wherein the damper device includes an input plate attached to acrankshaft of an engine, an output member configured to output a torqueto a transmission shaft, and an elastic member configured to elasticallycouple the input plate and the output member.
 12. The drive deviceaccording to claim 11, wherein the elastic member is a coil spring, anda center of the elastic member does not overlap the rotor of the rotaryelectrical machine in an axial view.
 13. The drive device according toclaim 1, further comprising: a starter ring gear configured to transmita power to a crankshaft of an engine, wherein the starter ring gear isdisposed radially outside a coil end of the rotary electrical machine,the starter ring gear overlapping the coil end in a radial view.
 14. Thedrive device according to claim 1, further comprising: an angle sensordisposed radially inside a center of a torus of the fluid coupling, theangle sensor disposed to overlap the torus in a radial view.